1. Field of the Invention
The present invention relates to a method and a system in which a client, intending to participate in a chat Push-to-talk over Cellular (PoC) group, presents session participation-invitation reservation to a server when the number limit has been exceeded pursuant to the policy of the chat PoC group, or when a chat PoC group ID exists but a corresponding session has not been initiated.
2. Description of the Related Art
With the rapid development of mobile communication and the spread of communication networks, numerous services and applications using a cell phone have been provided. Further, as user requirements are varying, a service is being developed from a simple communication service to such services as a location, a multimedia and a Push-To-Talk (PTT) service. Specifically, a PTT service supports various supplementary functions including instant messenger and a state indication, as well as group and voice communication which can be provided by the conventional radio or Trunked Radio System (TRS).
Recently, there has been active discussion regarding the standard establishment for a PoC service in which such a PTT concept is provided through a mobile communication network. According to the characteristics of a PoC service distinguished from an existing mobile communication service, a user belonging to multiple sessions can perform communication while navigating among the sessions. The requirements for this concurrent communication and navigation have been clearly defined in the Open Mobile Alliance (OMA).
According to a chat PoC session participation scenario, there may exist various reasons for which normal session participation is impossible, such as when the number limit of a chat PoC group stipulated in the policy of the chat PoC group has been exceeded or when the ID of the chat PoC group exists but a session has not been initiated. As described above, when the normal session participation of a client is impossible, the client must repeat a session participation request in order to participate in a session. Therefore, the Quality of Experience (QoE) of a transmission-side PoC client may significantly deteriorate.